In a variety of nano-device applications, high-speed (low-cost) fabrication of nanostructures with sharp shapes is important. This includes devices exploiting nanoscale phenomena in optics, magnetics and biomedical materials. Specific device applications where these types of structures are needed are discussed below.
In the area of nanophotonics, the following exemplary shaped structures shown in FIGS. 1A and 1B are desirable. FIGS. 1A and 1B illustrate structures 101, 102, respectively, where the gaps g1 and g2 can be as small as 2 nm, and points A and B (see FIG. 1A) are sharp corners with a radius of curvature as small as 1 nm.
In the area of magnetics, multi-bit magnetic random access memory can be achieved using exemplary structures as shown in FIG. 2A, where d1 may be <10 nm in size. Similarly for thin-film heads used to read and write data onto hard disk drives, the following shaped structures as shown in FIG. 2B are desirable, where d2 may be <10 nm.
In the biomedical area, the ability to make shape controlled nanoparticles are known to be of interest in targeted diagnostics and drug delivery.
Currently, the highest resolution large area nanopatterning is used to make non-volatile CMOS based memory, specifically NAND flash with 17 nm half pitch and bit patterned media for high density magnetic storage in hard disks. While this patterning has historically been performed by photolithography, the resolution of the most advanced form of photolithography—193 nm immersion (193i) lithography—has plateaued at a resolution of approximately 40 nm halfpitch. Higher resolution patterns are fabricated by self-aligned double patterning (SADP), extreme ultraviolet lithography (EUVL), and multiple e-beam lithography (MEBL), but these techniques suffer from high costs, low throughput and are restricted to patterning periodic features.
Unfortunately, nanoimprinting techniques are currently limited to fabricating elementary nanoscale structures, such as dots, lines, etc. Current nanoimprinting techniques do not possess shape control to allow it to create nanoscale patterns with complex shapes which could be used in a variety of areas, such as magnetic memory, nanophotonic devices based on plasmonic and metamaterial structures and biomedical applications.